You've encountered one of the big problems in user experience - platform diversity. Variable access conditions. Whatever you want to call it.
Did you know that some people can see farther into the blue spectrum than others - and others see less?
I've got a relatively clear differentiation between the two colours on my monitor. Well, one one of the screens I use. Of course, that's the monitor that calibrated for design/print work. I took a look at the screenshot on my phone, and the colours aren't nearly as well defined. I imagine that it'll be nearly the same on the old LCD I use in the workroom.
From an accessibility standpoint, it's an interesting decision. Would it be better if it was red/green? Probably not, if you're red/green colourblind. And perhaps the person who selected the colours can see a clear difference due to physical ability or monitor calibration.
So ... is there a better choice? Perhaps.
It depends on the purpose of the colour choice. Theoretically, what if UX:SE wanted the links to be similar, to increase the viewing on questions - perhaps prodding users to comment, re-comment, or edit previously viewed questions. I doubt that is the case (dark patterns and all), but there could be another deliberate reason, like visual consistency.
Or again, maybe they've got the contrast so high on their monitors that it doesn't appear to be remotely similar.